Calgarians will have to wait until Thursday for more information on relaxed water restrictions, as the City of Calgary will open valves to increase the pressure Monday afternoon.

Mayor Jyoti Gondek, along with Infrastructure Services GM Michael Thompson delivered a Monday morning update on Calgary’s water main situation, in a newly prescribed regimen of public updates.

In Monday’s update, GM Thompson said that they would be turning on a third tap at the Bearspaw water treatment plant to slowly increase the water capacity and flow to around 70 per cent.   Provided there are no setbacks with the pipe, that would allow for the further easing of restrictions.

“If all goes well after we turn on the additional pump, we will be at a 70 per cent flow, which will move us to stage two outdoor water restrictions on Thursday,” he said.  

“If things continue to go well, we will then look to move to stage one outdoor restrictions on Monday, July 22.”

City officials said they need to get to 75 per cent flow before removing all water restrictions.

“Our move today is trying to strike a balance,” Thompson said.

“We’re managing the risk between increased water flow, which will help lessen water restrictions and the pipe’s overall stability.”

Mayor Gondek said that acoustic monitors will be used after the pipe is turned on midday Monday, and they will watch for pressure increases and possible problems over the next 72 hours.

“I cannot stress enough that the next 72 hours are critical to understand how the pipe is responding to speed of flow. Turning on an additional pump means the pressure has to be carefully monitored, ensuring that we can identify any issues that may exist,” she said.

“It may be a situation where everything goes smoothly, or it may be a situation where increased speed and pressure lead to another hotspot that will need to be addressed.”

Thompson said that if that happens, outdoor water restrictions could be in place for longer.

“This is part of our calculated risk decision. After analysis, we think that the risk is low enough to move ahead with increasing the waterflow,” he said.

“If a new break were to happen, we’re ready to respond.”

Possible medium, long-term fixes being determined

In order to get to the point of increasing pressure, they’ve been learning more about controlling the pressure in the pipe using the Bearspaw water treatment plant pumps. It’s a reasonably substantial jump in pressure, going from 55 to 70 per cent.

“That’s really given us the confidence that we can go and turn on another pump today, which will increase the flow through the pipe,” he said.

“We’ve talked about the configurations we have and how we bring pressure and flow back into this pipe. This is the next step and so we’re ready to take the next step.”

Thompson said they know there are additional areas of weakness in the Bearspaw water feeder main that require future repair. Three additional wire snaps have been found since they turned the water back on.

 He said they’ve begun to develop options to address that need. Their decision will be aided by the recent use of a PipeDiver tool that inspects the pipe from the inside. Results of that analysis will be available at the end of July.

Some of the repair options being considered include a liner inside the existing pipe, replacing more pipe segments – specifically ones that have lower structure integrity due to the wire snaps – reinforcing segments of the pipe, or installing a new feeder main.

“We’re going to develop this plan in the next couple of months and we’ll be reporting back with more information when we have that available,” he said.

The capacity of the pipe prior to the June 5 break was roughly 400 million litres of water delivered per day, according to Thompson. When asked if the pipe, given its current state, would ever return to that capacity, he said they will see how the pipe respond to these pressure increases.

“We want to make sure that we’re really minimizing the risk to the pipe while making sure that we can serve the community,” he said.

Moving forward there will be live updates with Mayor Gondek on Mondays, Wednesdays and Fridays at 8:30 a.m., and then the daily 2 p.m. livestream briefings.